The invention is relates to the field of turbine design, and especially, to a turbine having foils whose attack angles are varied by computer control for increased efficiency.
Wind and water are energy sources which are widely available, renewable and clean, and the benefits of harnessing wind and water power are manifest. In comparison with the generation of electricity by burning wood, coal, or oil, the increased utilization of wind and water power improves the environment by reducing the emissions of carbon dioxide and other undesirable pollutants which adversely affect air quality and lead to acid rain, the greenhouse effect, and global warming.
Turbines have long been used to harness these energy sources to generate power in the form of electricity or mechanical energy. New turbine designs should therefore be more efficient to provide greater amounts of electricity for a given amount of fluid flow through the turbine. With more efficient turbine designs, the cost of energy generation from wind and water sources decreases. Electricity especially becomes less expensive to generate and more available. Of course, it is desirable that such turbines should be also relatively easy to design, manufacture, install, and maintain.
Wind and water provide slow fluid flows and while the total energy in these flows is large, the “energy density” of a slow flow is small. As a result, a mechanical system should be large to efficiently generate power from these fluid flows. In addition, since the direction of winds and ocean currents can change relatively quickly, a power generation system should be able to respond to these changes rapidly and efficiently. But the requirements of a large structure and the requirements of a mechanical system which can turn or move quickly in response to directional changes are incompatible and may be difficult to achieve.
Therefore, there is a great need for improvements in the generation of power from fluid energy sources which move slowly, i.e., wind and water sources.